Rob Townsend

Tag Archives: aperture

Take three photographs of a scene with depth to it, first at a wide-open aperture, then at a mid-scale aperture, then at a small aperture. Focus on the same central point. Observe the areas of sharpness in the resultant images.

Equipment:

Canon EOS 650D with EF 40mm f/2.8 STM lens

Method:

Very similar to previous exercise: I lined up a set of five condiments/jars from the kitchen cupboard, staggered in a slight diagonal line so that each was visible in the viewfinder. I chose the middle jar as the focus point and did the three shots at f/2.8, f/9 and f/22.

Results:

With the widest aperture, only the coffee jar in the middle is sharp, with readable text and defined edges:

f/2.8

With a mid-range aperture setting, the honey on the left and to a slightly lesser degree the salt on the right both fall into the sharp zone while the two items on the outside remain blurry:

f/9

At the smallest aperture the entire image is sharp enough to make out the text on all of the labels, and the wooden surface on which they are placed shows its grain pattern.

f/22

What I’ve learned:

This exercise was good for demonstrating a concept that I was familiar with, that of controlling the depth of field using aperture settings. The two extreme examples can have specific applications, such as bringing focus to one part of the image (widest aperture) as in a portrait or a macro shot, or drawing the viewer’s eye in through the image foreground->centre->background in more of a narrative way (smallest aperture), as you might for a landscape shot with a great deal of depth to it.

Take three photographs of a scene with depth to it, at the same wide-open aperture but with the focus on three different positions.

Equipment:

Canon EOS 650D with EF 40mm f/2.8 STM lens

Method:

Very straightforward: camera on tripod, bottles lined up on tabletop, selected focus point first on foreground, then on middle then on background.

After doing it with beer bottles, I repeated the exercise with playing cards, just to see if the principles of where I preferred the focal point held true.

Results:

Bottles – near focus

Bottles – mid focus

Bottles – far focus

With this set of images I had a clear preference for the one with near focus. It just seemed most ‘natural’ that the foreground is sharpest and that objects further away would be more blurry. This seemed to help to imply the depth as it in some way mimicked the human eye. Also, there may be something in the theory that the eye reads a photo from left to right and settles on the lower right portion. This is why I tried the alternative set of images with the cards, as a comparison.

My second favourite was the one with far focus. This one seemed to lead the eye towards the sharper portion of the image and so had more implied movement, whereas the close focus one seemed more static, or ‘grounded’.

The least satisfying shot was the middle focus one. It just lacked interest. You look right into the middle of it and… that’s it.

As mentioned above, I did an alternative set with playing cards, to test the theory. I also wanted to make sure I wasn’t getting distracted by the subject matter…!

Cards – near focus

Cards – mid focus

Cards – far focus

This set confirmed my findings with the bottles in that my preference is for the one with the sharpest foreground. Again it seems most ‘natural’ and needs least interpretation. In this instance, the sharp foreground covers both the left and right side of the finished shot, which makes me surmise that the focal sharpness is probably more significant than the absolute position in the frame.

In this example, I found both of the other variations lacking. This may be as the cards have a flatter focal plane, and the gaps between the objects are smaller, meaning less of a sense of depth than with the bottles.

What I’ve learned:

I was already aware of how to focus on one portion of an image to control depth of field and draw the eye, and I think when I do this I naturally tend to focus on the foreground anyway. I hadn’t however done an exercise like this before to do a direct comparison between different points of focus. What I have learned here is that one can choose to add a little more… interest? (interactivity? mystery?) into a photo by moving the focal point towards the rear of the scene, as this inherently makes the eye move into the image.